Mario Balotelli is the joker in Roberto Mancini's Manchester City pack who returns to action after a four-match domestic ban as the club's European quest resumes in the competition that may or may not prove distracting to their title aspirations: the Europa League.

As a troubled Carlos Tevez embarked on the first day of a fitness programme at City's Carrington training base, Balotelli checked back in with the match-day squad, training on the Estadio de Dragão pitch before the opening leg against Porto, the holders, in Thursday's last-32 tie.

After Mancini told Tevez in strident terms that he had, in fact, treated him "too nice", and not like a dog as the forward claimed, the Italian was equally frank when admitting he has pleaded with another of his more individual performers to "have good behaviour on the pitch and think to only play football".

On Thursday evening Balotelli comes face to face with Cuneyt Cakir, the Turkish referee, who gave him the second of his four red cards with City – in the last-16 stage of this competition, against Dynamo Kiev, nearly a year ago. Mancini is conscious of this and of how Balotelli could still prove a prime mover in City's two-pronged attack in the Europa and Premier Leagues.

Reminded of the Turkish official sending Balotelli off for a lunge at Goran Popov, Mancini said: "I have spoken to Mario two weeks ago. I said: 'Please, we have 13 games to play [in the league] as well as the Europa League – try to have good behaviour on the pitch and think to only play football."

Balotelli last featured on 22 January in City's 3-2 win over Tottenham Hotspur, receiving a retrospective red card for a stamp on Scott Parker. Before this the 21-year-old had illustrated his worth by winning and scoring the penalty that claimed the three points. Mancini said of his potential worth as the season moves into its business phase: "Mario is an important player for us, he has a good quality. He can play with Edin [Dzeko], with Sergio [Agüero].

"I think if his head will be OK in the next two months, he will be an important player. It's difficult to find a good definition for him. We know that Mario is a fantastic player. He's young, sometimes he will do some mistakes but for this reason, if he can keep his composure for the next months, he will be an important player for us, in the Europa League and the Premier League.

"It's my opinion that at this moment all the players will be important. It's important for me to have all players between now and the end of the season. If we want to get to the final of the Europa League or win the Premier League, it's important to have all players ready and available for all games. Mario is one of them. Now we'll have three strikers for tomorrow, I think that's a good thing for me and for this game."

Balotelli is likely to line up alongside Dzeko and David Silva in an attacking trident at the head of a 4-3-3. Less likely to start are the Touré brothers, Yaya and Kolo, who flew into northern Portugal straight from the disappointment of losing the Africa Cup of Nations final on penalties to Zambia. The manager said of their potential involvement: "I don't know. Before I need to speak to them and tomorrow it will be decided. They arrived here this morning."

Of the challenge against Porto, led to the Europa League title by André Villas-Boas last season, Mancini said: "Porto usually have really good players. In this team they have many good players, I think. I don't know but Danilo I followed him for a year, the right-back, fantastic player, he's young. But they have Hulk, [Cristian] Rodríguez, [João] Moutinho, they are all good players.

"Usually it's better to play away the first game but in this case I don't think there will be a difference. Tomorrow will play two strong teams and anything can happen in this game and the [return] game in Manchester [next week]. I don't think either is more important.

"I think that it is one of the big games at this stage because we play Porto, a top team who have played Champions League. At home they are very strong, last year they won the title, tomorrow will be very hard for this reason but I think it will be a very good game."